Well tubing signal marker for magnetically actuated tool



March 2, 1965 w. G. owNBY 3,171,488

WELL. TUBING SIGNAL MARKER FOR MAGNETICALLY ACTUATED TOOL.

Original Filed April 19. 1961 VV. 6. Ouv/76g lNvENTOR.

BY QC. @mi

ATTORNEY United States Patent O 4 Claims. (Cl. 166-65) This invention relates to well working equipment and more particularly to the signaling of work at a selected depth in a well hole.

This application is a division of copending application SN. 104,051, filed April 19, 1961, disclosing a self contained tool which is triggered into action by electromotive force generated by tool travel through a signaling field. A signaling field is provided at one or more downhole stations within a well tubing string assembly. Each station involves a magnetic field protruding inwardly from the tubing wall 4for effecting response of a tool carried field influenced component presented to the magnetic field.

It is an object of this invention to provide a well tubing string embodying a signal marker means through the use of alternately successive magnetic and nonmagnetic tubular sections coupled in end to end relation and with the end portions of a pair of magnetic tubing sections which are spatially separated by an interconnecting nonmagnetic section, constituting axially spaced apart terrestrial magnetic poles of opposite polarity.

Another object is to provide a tubing string having a number of spaced apart signaling stations, each comprising a set of magnetic fields differently spaced apart relative to the field spacing in other sets whereby any station can be selected for infiuencing operation of well tools having signal responsive components which are or can be set in spaced apart relation matching the spacing of the magnetic fields at any given station.

Additional objects and advantages will become apparent from the accompanying drawing wherein:

FIG. 1 is a part elevation and part vertical section of fragments of a tubing string signaling station and a well tool positioned therein;

FIG. 2 is a view similar to FIG. l, showing a second station and a tool in work performing relation thereto; and

FIG. 3 is a vertical sectional view of a portion of a tubing string and magnetic field providing signaling stations in modified form.

Referring to FIGS. 1 and 2, there are illustrated fragments of wire line running tools Whose operating components in each instance are electrically actuated when a circuit is completed through a pair of semiconductor rectiers supplied with bias voltage upon concurrent passage of a pair of transducers through magnetic fields of a tubing string station, as detailed in the patent application of which this application is a division.

As here shown, the tool body includes a coupling section 108C and a nonmagnetic section 108d. Within the nonmagnetic section 108d of the running tool is contained the field sensing subassembly including the two coils 40 and 41 and their mounting spools 128 held on the mounting spindle 131 in fixed longitudinal distance apart by the spacer tube 130. The spacer tube 130 is of a length to position the detectors at maximum spaced apart relation on the mounting spindle 131. By substituting spacer tubes of other lengths, the distance between the coils can be selectively varied. Thus the running tool structure just described is also shown in FIG. 2 except that spacer tubes 231 and 331 have been substituted for decreasing 3,171 ,488 Patented Mar. 2, 1965 the longitudinal dimension between the pair of co-operating coils.

In certain regions of the earth, terrestrial magnetism will provide signaling fields through the use of a tubing string structure as shown in FIGS. 1 and 2. The tubing string will have its walls constructed of magnetic material except for short length circular inserts for providing a signaling station. Thus in FIGS. 1 and 2, tubing portions of ferromagnetic material are indicated at 50-50 and short length nonmagnetic ring inserts are shown at 51-51. The nonmagnetic rings 51 in FIG. 1 are spaced apart similar to and in length generally correspond with the coil spools 128. The spacing can be varied as required, as indicated comparatively by FIGS. 1 and 2. In each instance, the earths magnetism will afford magnetic poles of opposite polarity immediately above and below the ends of the nonmagnetic rings where they are welded or otherwise connected to the magnetic tubing sections. In the Northern Hemisphere, a north magnetic pole will be above and a south magnetic pole below each nonmagnetic insert and therefore the lines of force will flow longitudinally within the field between the poles. The lines of force will be upwardly in the Southern Hemisphere. In either event, the coil windings will be determined for imposing electromotive force of proper polarity on the semiconductor with reference to the direction of relative movement between the coil and the field and direction of lines of force in the field.

Considering that the coil windings are arranged for use in the Northern Hemisphere, then downward travel of a tool whose detector coils are spaced apart to match the field spacing of a given one of several marker stations, each having eld spacing different from the others, an electromotive force of positive polarity will be generated as each coil traverses each field. However, tool actuation can occur only when both detector coils simultaneously traverse fields and supply bias voltage to the serially connected semiconductor rectifiers.

In FIG. 3, a single insert ring 151 of nonmagnetic material is welded in end to end succession with tubing string sections of magnetic material so that the earths magnetism provides a north pole above and a south pole below the nonmagnetic insert for the Northern Hemisphere. The axial length of the insert 151 is such that the lines of force in the field between the north and south poles can be simultaneously swept by both of a pair of sensing coils spaced7 for example, as seen in FIG. 2.

In some instances, it will be feasible to use the same field spacing at all marker stations and still obtain selective tool actuation at a given station. For co-operation with any one of identical single field markings at several stations in the same tubing string, the running tool coil windings and connections should be such that positive polarity Voltage on the semiconductors will be generated by coil travel upwardly through the magnetic fields. Thus running tool response is not triggered by tool descent and for selective actuation, the tool will be run downwardly to the predetermined depth below the station at which the work is to be performed. Upon reverse movement, the firing circuit will be closed at the instant tool movement carries the set of spaced transducers through the extended magnetic field above the point at which the direction of travel was reversed.

Modifications in the structure as specifically described can be made without departing from the invention as set out in the appended claims.

What is claimed is:

1. For utilization of terrestrial magnetism as a downhole signal marker in a well tubing string within the earth, said signal marker comprising a succession of end to end joined together tubing string sections of which certain of the sections are .of ferromagnetic material and are magnetized as dipole magnets by inductive action of the earth, others of the sections being of nonmagnetic material, the nonmagnetic sections being longitudinally spaced from one another and interposed between the poles at adjoining ends of adjoining dipole magnet sections, for protrusion inwardly at each nonmagnetic section of a magnetic field between adjoining poles of opposite polarity.

2. For utilizing the action of terrestrial magnetism on a tubing string within the earth to induce a field to which a iield sensing Well tool will respond, a magnetic field signal station comprising a succession of end to end joined together tubing string sections positioned in a wellhole, which sections are alternately of ferromagnetic material and nonmagnetic material for induction of magnetism in the magnetic sections to thereby present dipole magnets whose ends, Which-are spaced apart by an intervening nonmagnetic section, constitute magnet poles of opposite polarity and provide a magnetic iield protruding inwardly of the tubing string.

3. For signalling the operation of a well tool at a downhole location, a running tool having a pair of longitudinally spaced apart iield sensing elements, magneticsignalling means providing two longitudinally vspaced apart cooperating terrestrial magnetic ields in a tubing assembly comprising a series of tubing sectionslsecured within a wellhole in end to end succession and comprised in successive order of a section of magnetic material, a section of nonmagnetic material, a section of magnetic material of a length substantially corresponding to the longitudinal space between said field sensing elements, a section of nonmagnetic material and asection of magnetic material, whereby magnetism of theearth provides twin spaced apart dipole fields, one across each nonmagnetic section and between the Vopposite polarity ends of the magnetic sections joined to such nonmagnetic section.

4. For signaling operation at a downhole well location of a running tool having a pair of magnetic iield responsive transducers, a dipole magnetic eld signaling station within a tubing assembly contained within the earth, said dipole magnetic iield signaling station consisting of a tubular section of nonmagnetic material and a pair'of f tubular sections of magnetic material joined in end to end succession with the nonmagnetic tubular section and' mag-k netized by action thereon of terrestrial magnetism to present opposite polarity poles at the adjacent endsof the magnetic sections joined by said tubular lsection of lnonmagnetic material.

CHARLES oCoNNELL, Primary Examiner.y 

4. FOR SIGNALING OPERATION AT A DOWNHOLE WELL LOCATION OF A RUNNING TOOL HAVING A PAIR OF MAGNETIC FIELD RESPONSIVE TRANSDUCERS, A DIPOLE MAGNETIC FIELD SIGNALING STATION WITHIN A TUBING ASSEMBLY CONTAINED WITHIN THE EARTH, SAID DIPOLE MAGNETIC FIELD SIGNALING STATION CONSISTING OF A TUBULAR SECTION OF NONMAGNETIC MATERIAL AND A PAIR OF TUBULAR SECTIONS OF MAGNETIC MATERIAL JOINED IN END TO END SUCCESSION WITH THE NONMAGNETIC TUBULAR SECTION AND MAGNETIZED BY ACTION THEREON OF TERRESTRIAL MAGNETISM TO PRESENT OPPOSITE POLARITY POLES AT THE ADJACENT ENDS OF THE MAGNETIC SECTIONS JOINED BY SAID TUBULAR SECTION OF NONMAGNETIC MATERIAL. 